1. Field of the Invention
The present invention relates to a monoazo metal complex compound containing composition exhibiting almost no skin sensitization potential, a production method therefor, a charge control agent comprising the monoazo metal complex compound containing composition, a toner for developing electrostatic images that contains the charge control agent, a coloring agent containing said monoazo metal complex compound containing composition, and a colored thermoplastic composition containing said monoazo metal complex compound containing composition as a coloring agent.
2. Description of the Prior Art
Skin sensitization is a contact allergic reaction induced by skin contact with a simple chemical substance, a metal, or the like, and is a form of skin allergy (e.g., allergic contact dermatitis). The term allergy is defined as an inflammation reaction due to antibody production by the living body. Sensitization refers to the entry of an antigen in the living body to cause an antibody to be produced. In recent years, an emphasis has been placed on the potential of compounds for inducing skin sensitization in view of their safety.
Examples of reported cases wherein the safety of chemical substances posed a problem include a case of a chlorinated phosgene compound produced from a reaction of sodium hypochlorite and a yellow dye in a DC brand sweater [Hifu/Skin 1989;31 (Supple. 7):24-33], a case of the grounder naphthol AS remaining on cloth in a cotton flannel night clothes [Eiseikagaku/Journal of Hygienic Chemistry 1986; 32(5):359-67], a case of the grounder naphthol AS-f) remaining on cloth in a cotton flannel night clothes [Environ. Dermatol. 1995; 2:278-82], a case of Disperse Red 153, Disperse Blue 106, and Disperse Blue 124 in one-piece dress [Contact Dermatitis 1996; 34:6-11], a case of the azo disperse dyes Disperse Yellow 3, Disperse Orange 3, and Disperse Red 17 formulated as coloring agents in plastic eyeglass frames [Environmental Dermatology 1994; 1(Supple. 1), 50], and a case of Solvent Orange 60 formulated as a coloring agent in plastic eyeglass frames [Environmental Dermatology 1998;5(Supple. 1):92]. As the demand for regulation of the skin sensitization potential of compounds is increasing, it is of paramount importance from the viewpoint of safety to assess the allergic reaction of new chemicals and newly launched commercial products.
For determining the sensitizing potential of such chemicals, there have been proposed new methods, including the Beuhler test method, which simulates actual use in the human body, and the maximization method, which determines the potential of the test compound. As a result of the meeting of experts of the Organization for Economic Cooperation and Development/OECD held in May of 1991, the OECD guidelines were presented, in which priority is given to the Beuhler test method and the maximization test of Magnusson and Kligman using the guinea pig (maximization test method).
Monoazo metal complex compounds are used for various applications, occupying an important position in the industry. Major applications include dyes used to impart colors for writing inks, recording inks (including inkjet inks), leather, plastics, etc.; coloring matters based on absorption of ultraviolet light, near infrared light, infrared light, etc.; and charge control or enhancement agents used in toners for developing electrostatic images and resin powder paints for electrostatic painting.
These applications of monoazo metal complex compounds all call for consideration of effects on the human body and the environment, in addition to the performance required for the applications. In the case of monoazo metal complex compounds as charge control agents, for example, their effects on the human body and the environment as compounds, as well as their charge characteristics, must be taken into consideration.
Regarding effects on the human body, skin sensitization potential tests for compounds provide an especially important set of safety data. In recent years, priority has often been given to assessment of skin sensitization potential based on the aforementioned maximization method.
However, because of the production method, monoazo metal complex compounds have impurity substances from starting materials, and byproducts and impurity substances associated with metallization, resulting in problems to be solved in skin sensitization assessed using the maximization method.
Accordingly, the object of the present invention is to provide a monoazo metal complex compound containing composition characterized by high safety to the human body and a low incidence of skin sensitization in skin sensitization tests, especially the maximization method, a production method therefor, a charge control agent comprising the monoazo metal complex compound containing composition, a toner for developing electrostatic images that contains the charge control agent, a coloring agent containing said monoazo metal complex compound containing composition, and a colored thermoplastic composition containing the monoazo metal complex compound containing composition as a coloring agent.